The Asset Owners 100 ( AO100 ), the world’s 100 largest asset owners, grew by 6% last year to reach over US$20 trillion, according to research from the Thinking Ahead Institute. Pension funds remain the single biggest group of asset owners, accounting for over 60% of assets, followed by sovereign wealth funds ( 32% ) and Outsourced Chief Investment Officers ( OCIOs ) and Master Trusts combined ( 7% ).